Protecting Your Vote: In South Texas, the myth of noncitizen voting takes center stage

This story is part of ABC News' monthlong series "Protecting Your Vote," profiling people across the country who are dedicated to ensuring the integrity of the voting process.

Cecilia Castellano awoke to the sound of her doorbell in the early hours of Aug. 20. The South Texas sky outside her Atascosa County home was still dark, but as she emerged from her bedroom -- hair curlers in place, a robe draped over her shoulders -- a light cut across her foyer.

Two voices on the other side of her front door announced themselves: "Police Department."

"I came to the front and I actually looked out through the window ... and they were shining a flashlight in my window," Castellano recalled in an interview with ABC News' Mireya Villarreal. "They said, 'Ma'am, we have a search warrant.' I said, 'A search warrant for what?' And they're like, 'Well, can we come in?'"

The officers presented Castellano with the warrant, then confiscated her phone and asked her to write down its PIN, she said.

They were searching for evidence of so-called "vote harvesting," an opaque provision of a 2021 voter integrity bill championed by the state's Republican Gov. Greg Abbott and enforced by its controversial attorney general, Ken Paxton.

Both men have characterized the law, known widely as S.B. 1, as a safeguard against noncitizen voting -- an exceedingly rare occurrence already banned under state and federal law. But Castellano, a Democratic candidate for a seat in the Texas State House, calls it voter intimidation.

"All I have done -- all my team has done -- is gone and knocked on doors," Castellano said. "That's why I was caught off-guard. And to this day, I've gone from being scared, to being angry, to [thinking] they have violated my civil rights -- they have truly tried to intimidate me."

A third-generation Mexican American, Castellano -- who is a grandmother and a business owner -- launched her longshot bid for public office with no expectation of earning widespread attention. But in the aftermath of Aug. 20, her campaign has emerged as a flashpoint in the national debate over noncitizen voting.

Castellano was among several prominent Latinos in Texas who were targeted in connection with Paxton's vote harvesting probe, which he said was precipitated by "sufficient evidence" of election fraud. A county prosecutor outside San Antonio referred allegations of "election fraud and vote harvesting" to the attorney general's office in 2022, according to Paxton's statement in August.

No charges have been filed in the case.

"Why are they coming to the areas where it's predominantly Latinos?" Villarreal asked Castellano.

"Because they're trying to intimidate the Latinos," Castellano replied.

Republicans, following the lead of former President Donald Trump, have claimed without evidence that undocumented immigrants could tilt the scales in favor of Democrats this November, increasingly promoting the debunked narrative as a centerpiece of their pitch to voters in the months leading up to Election Day.

"Our elections are bad," Trump said at ABC News' presidential debate in September. "And a lot of these illegal immigrants coming in, they're trying to get them to vote. They can't even speak English, they don't know even know what country they're in practically, and these people are trying to get them to vote, and that's why they're allowing them to come into our country."

House Speaker Mike Johnson, a Republican, recently tried without success to pass legislation that would have required voters to prove their U.S. citizenship through documentation -- instead of attesting to it under penalty of perjury as the current laws require -- arguing in May that, "We all know, intuitively, that a lot of illegals are voting in federal elections."

But critics and election experts say that simply isn't true, and they accuse Trump and his allies of generating unfounded and disingenuous claims of noncitizen voting as part of an effort to make it more difficult for eligible voters to register and vote. The libertarian Cato Institute called allegations of widespread noncitizen voting "alarmist theorizing," and the Republican elections chief in Pennsylvania recently acknowledged that he "found that it occurred very, very, very infrequently."

The Brennan Center for Justice, a nonpartisan think tank, found that fewer than 0.0001% of the votes cast in the 2016 election were made by suspected noncitizens.

"Noncitizen voting is a vanishingly rare phenomenon," said Sean Morales-Doyle, a voting rights expert at the Brennan Center. "It is a felony offense for a noncitizen to either register to vote in state and federal elections, or to vote. The consequences include prison time, they include hefty fines, and they include deportation."

"It is just mind-boggling to think that someone who has decided to move themselves and their family to the United States and try to build a life here is going to risk all of that -- risk their freedom and their presence in the United States -- to cast one ballot in one election," he said.

Even so, leaders in a handful of GOP-led states have wielded the threat of large-scale noncitizen voting to justify mass purges from their voter rolls, including in Tennessee, Alabama, Ohio, and Texas -- where Gov. Abbott has boasted of removing more than a million names from the rolls since 2021, when S.B. 1 was passed.

In Virginia, Republican Gov. Glenn Youngkin said he removed more than 6,000 individuals suspected of being noncitizens from the state's voter rolls -- but a Washington Post investigation found not a single example of noncitizen voting during his term. And on Friday, the Justice Department sued Virginia for allegedly violating federal rules that ban states from removing voters from the rolls within 90 days of an election. Youngkin called the lawsuit a "politically motivated action" meant to "interfere in our elections."

As the national debate over noncitizen voting rages on, Castellano has vowed to continue her campaign. During a recent afternoon of door-knocking in Jourdanton, Texas, where she was trailed by a group of reporters, two police cruisers approached Castellano.

"I'm actually the candidate for state representative for House District 80," Castellano told the police officers, explaining that the cameras following her were reporters tracking her campaign.

"I look forward to earning y'all's vote -- the men in blue, the women in blue," she told the officers.